Fig. 16-Twisted Shaft

AXLE-REAR

MOTOR TRUCK SERVICE MANUAL

Fig. 16 illustrates a portion of a twisted axle shaft caused

by abusive or very severe operation.

Such parts condition is produced by severe operations

frequently in combination with abusive handling of

This is a preliminary failure stage where the shaft has

equipment.

Usually investigation will disclose the

twisted and alignment was destroyed, but no signs of

vehicles are overloaded or the drivers are improperly

fracture are in evidence. The shaft has passed its period

using the equipment.

of usefulness and should be replaced. If it is not, it will

continue to twist until an ultimate fracture will occur.

Technically the damage is the result of a series of torque

With complete failure, other axle parts may be damaged

or stress applications greater than the strength of the

with consequent substantial increase in repairs cost.

metal. Most always these are in both directions and

The lubricant should be changed and the axle well

applied thru low and reverse transmission gears. A

cleaned after such shaft breakage to eliminate all

twisted shaft that has fractured is sometimes thought, by

possibility that pieces might remain in the unit to cause

persons not experienced in metal fractures, to be

later damage. The shaft on the opposite side of the

evidence of seams in the steel It is not, for the small

truck should be very carefully examined.

noticeable cracks are caused by fatigue.